Interesting. Is it in the tradition of open source CAS systems like Maxima, Yacas, Axiom, etc.? If I remember correctly, I think there was an online version (Java?) of Yacas.

The upcoming Geogebra3D looks like it will incorporate more CAS functions as well.

Do you have more information about what your program will be used for? How is it different or similar to other projects? That may help us suggest a name.

I was going to make it just line by line function building such as-
f(x):=sin(x)+x
g(x,y):=f(x)^(integral(f(y),y,lowerbound,upperbound))
g(2,3)= and it solves the above

The only thing I wanted to do different was once you finish your work with a file you could save it and even make it public. By making it public people could import that work into their doc and obviously you could import someone else's work into your document.